\begin{tikzpicture}[>=Stealth,
    every node/.style={fill=white, inner sep=1pt},
]
    \tikzset{
        pics/yuan/.style n args={2}{
            code = {
                \pgfmathsetmacro{\r}{#1}
                \draw [fill=white] (0, 0) circle (\r);
                \draw [<->] (-\r, 0) -- (\r, 0) node [midway] {$\phi \; #2$};
            }
        }
    }
    \pgfmathsetmacro{\a}{1.5}
    \pgfmathsetmacro{\b}{.75}
    \draw [pattern={mylines[angle=45, distance={5pt}]}] (0, 0) circle (\a+\b);
    \draw (0, 0) ++(160:\b) pic {yuan={\a}{a}};
    \draw (0, 0) ++(340:\a) pic {yuan={\b}{b}};
\end{tikzpicture}

